The present invention relates to turning and advancing rolled stock, particularly elongated stock for, of and in a pilgrim step type rolling mill, wherein specifically, the work piece such as a rolled stock is gripped between transport elements of the endless variety pertaining to a stock advancing device, and being capable of turning on a longitudinal axis of the rolled stock.
Cold rolling with a reciprocating rolling stand requires that occasionally, e.g. on each stroke of the frame, that the work piece and rolled stock be turned by a certain angle, and the stock also advanced. The known devices provide for the turning and for the advancing in separate steps and by means of separate devices. In each instance the movement, whether rotation or advance, has to be transmitted from a motion producing device, through the clamping structure on a carriage upon the work piece. From a practical point of view these movements are imparted in stock on the dead center position, or in a return point of the frame as this occurs on account of the regular pilgrim step motion. Rotating and advancing can be carried out separately because for each there are two dead center points and positions per cycle. Alternatively, turning and advancing can be superimposed and carried out concurrently in one or both of the dead centers. After the clamping carriage together with the work piece it holds has reached a particular terminal position the clamps are opened and the carriage is retracted. Now the mill is stopped. This stopping of the mill and feeding of the device is time consuming. Moreover, the tolerances are actually changed in each instance as far as the equipment and the rolled stock is concerned since this frame stops on the rolled stock and any change in temperature directly interferes with the dimensional tolerances.
Certain continuously working structures and mills are known, e.g. those of the kind described in the German printed patent application 20 34 315. These structures are of economical construction for the following reasons. The stationary turning and advancing device is characterized by endless transport elements. The work piece is gripped by an advancing structure that acts between the endless transport elements. The advancing device is, in addition, rotatable about a longitudinal axis. Rotation and advance is transmitted on the work piece in this case through a device characterized by a device 8 rather compact design and being designed to avoid slippage. The device includes endless elements such as belts, chains or the like movably arranged in a rotatable casing, frame or housing. This housing and the advance structure are driven through transmission trains and the several trains are connected to a common main drive and transmission. One transmission train provides rotation, and the other one provides advance. Both of them are interconnected through a planetary gear. The rotation of the housing will not advance the transport element, for the advance and vice versa. To deal with this problem, and because of the transmission ratio in the planetary gears, the wheel for the pinion that meshes the gear of the advancing transmission is rotated synchronously. A rotation of the worm relative to the casing is thus excluded. The advance may be changed through control in the particular transmission branch. The rotation of the housing together with the advance device, does not interfere with the advance itself.
The known structures, basically, operate satisfactorily but have the disadvantage of a very high degree of complexity and, therefore, of expenditure. In particular, interposing a planetary gear between two transmission trains constitutes a formidable cost factor. Moreover, the time for rotating and advancing is predetermined because of certain cam devices on a cam structure. The mode of operation can be changed only through an exchange in the cam arrangement. This kind of transmission is very expensive to make and to operate.